April 2, 2013 | 1:17am ET

The Blackhawks might be set at the center position with the acquisition of Michal Handzus on Monday, but the team still wants to add a defenseman.

Blackhawks GM Stan Bowman is in the market for a mobile defenseman, but after failing to acquire Lubomir Visnovsky from the New York Islanders, his options are limited.

On Monday, the Calgary Flames traded blueliner Jay Bouwmeester to the St. Louis Blues, while the Buffalo Sabres dealt rearguard Robyn Regehr to the Los Angeles Kings.

"There aren't a lot of sellers really; that's the bottom line," Bowman told the Chicago Sun-Times. "There's not a lot of trades. There still isn't a whole lot of separation -- a few teams maybe that are looking at next year and have given up hope this year. But for the most part, there's a lot of teams that still think if they get on that run in the last month here, they can get in. So they're hesitant to start trading players away."

"It's our job to keep making those phone calls, and we've had a lot of meetings internally about guys," Bowman said. "It has to make sense for us. We've had a good run with the guys we have so far. We don't really want to change that mix -- we're looking to add to it."